Work out what X% of a number is, what one number is as a percent of another, and percentage increase or decrease.
Percentages come up constantly, in discounts, tips, exam scores, and growth figures, yet the exact wording of the question decides which calculation you need, and mixing them up is easy. This Percentage Calculator handles the three most common versions in one place, what a percent of a number is, what one number is as a percent of another, and the percentage change between two numbers, so you always start from the right formula.
You choose the type of question and fill in the two values it asks for. For a straight percent, you enter the percentage and the number. For a share, you enter the part and the whole. For a change, you enter the original and the new value. The answer appears immediately, and you can switch between the modes without losing your place, which is handy when a real problem needs more than one of them.
The methods are simple once the right one is picked. A percent of a number multiplies the number by the percent divided by a hundred. One number as a percent of another divides the first by the second and multiplies by a hundred. Percentage change subtracts the old value from the new, divides by the old, and multiplies by a hundred, coming out positive for an increase and negative for a decrease. As an example, going from 200 to 250 is a fifty over two hundred rise, which is a 25 percent increase.
Reach for this rather than a plain calculator when the phrasing is the hard part, because keying the numbers is never the problem, choosing whether you want a share or a change is. It saves you from the classic error of computing a percent of the wrong base, or reporting an increase when the question asked for the decrease.
People use it to check a shop discount, to see what mark they scored as a percent, to work out a percentage tip, to measure how much a price or a salary went up or down, and to verify a statistic quoted in an article. Because all three modes sit together, you can move from one to another as a task demands.
The whole thing runs in your browser. The numbers you type are never uploaded, there is no account to make, and nothing is kept after you close the tab, so the only limit is your device. Use it as often as you need for everyday percentage questions.
Percentage change is the relative move divided by the original value, while percentage points are a simple subtraction of two percentages. Going from 10 percent to 15 percent is a 5 percentage point rise but a 50 percent increase, and confusing the two is a common mistake.
Find the discount amount as a percent of the original price, then subtract it from that price. For example, 20 percent off 500 is 100 off, leaving 400, and the tool's percent-of mode gives you the 100 directly.
A negative result means the new value is lower than the original, so it represents a decrease. The sign is meaningful, positive for growth and negative for a drop, which is why the tool keeps it rather than showing an absolute number.
Use the mode that expresses one number as a percent of another, entering your score as the part and the total as the whole. Scoring 42 out of 50 becomes 84 percent, without you needing to remember the divide-and-multiply steps.
The built-in modes cover percent-of, share, and change, so a reverse calculation takes a little rearranging rather than a single button. To undo a known percentage increase you divide the final value by one plus that percent expressed as a decimal.
It shows a practical number of decimal places for everyday use, so very long repeating decimals are trimmed for readability. For most discounts, tips, and scores that rounding makes no meaningful difference to the answer.
For normal everyday figures there is no practical limit, since the calculation runs locally in your browser. Extremely large numbers are handled to the precision your device supports, which is far beyond typical use.
Polished Pixels. All tools. About. Contact. Every tool runs in your browser and your files are never uploaded.